Phospha- prefix

In order to avoid ambiguity, it was previously recommended that these prefixes be modified when names already preempted for noncyclic compounds would otherwise be generated. The recommendation was that when immediately followed by -in or -ine, phospha- be changed to phosphora , arsa- to arsen- and stiba- to antimon-. This recommendation has been superseded by a suitable change in the stem suffix (see ahead), but is mentioned here because it is still substantially used in modern literature, including other chapters of this present work. 

The prefixes are the normal replacement prefixes (see Replacement Nomenclature, page 50), although elision of the final a often occurs. The prefixes are cited in the following order fluora-, chlora-, broma-, ioda-, oxa-, thia-, selena-, tellura-, aza-, phospha-, bora-, and mercura-. Chemical Abstracts does not use Hantzsch-Widman names for rings containing silicon. 

As wUl be seen later, there are also fuUerenes with one or more carbon atoms being substituted by other elements. In fuUerene nomenclature these molecules are described by prefixing to the name the designating syllable for the respective hetero atom, for ejample, aza[70]fullerene C69N, bis(aza[60]fullerene) (C59N)2, bora[60]fuUerene C59B, or phospha[60]fuUerene C59P. 

The heteroatom is given a name and is used as a prefix N, aza- O, oxa- S, thia- P, phospha- As, arsa- Si, sila- Se, selena-, B, bora, and so on. The a ending is dropped if the next syllable starts with a vowel. Thus aza-irine is properly written azirine. ... 

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